Some specific causes of urban heat island include manmodified landscape example. Aug 23, 2016 the urban heat island uhi, the phenomenon of higher temperatures in urban land than the surrounding rural land, is commonly attributed to changes in biophysical properties of the land surface. Even the case of tampa is not entirely incompatible with that view because there. Urban heat island in hong kong department of architecture, chinese university of hong kong page 4 of 24 period. This paper presents the development of a simulation model, which was incorporated into a geographic information system gis in order to calculate the maximum intensity of urban heat islands uhi max based on urban geometry data using a hw parameter. Martinvide j, sarricolea p and morenogarcia mc 2015 on the definition of urban heat island intensity. Creating and mapping an urban heat island index for california 5 mb, pdf executive summary pdf appendix a pdf appendix b pdf appendix c pdf appendix d pdf individual maps and data files. Using modis data from 2003 to 2012, we showed that the uhi effect decayed.
If youre looking for a free download links of heat islands. Urban heat islands uhi facts environment for kids mocomi. Some sample input files are included in the downloaded zip file create custom input file for your city. An urban heat island uhi is an urban area or metropolitan area that is significantly warmer than its surrounding rural areas due to human activities. Urban heat island uhi has become one of the worlds leading urban environmental issues. Compendium of strategies describes mitigation measures that communities can take to address the negative impacts of urban heat islands. The urban heat island uhi, the phenomenon of higher temperatures in urban land than the surrounding rural land, is commonly attributed to changes in. During the creation of these lessons, various potential explanatory rasters were investigated, including elevation, distance to industry, distance to open spaces. This one will be about urban heat islands in atlanta, but what is true for atlanta is true for new york city. Uhi is most noticeable during the summer and winter. It is important, however, to distinguish between the types of uhi for example, one defined by surface or air.
Using different types of kriging in the geostatistical wizard, youll interpolate temperature measurements and incorporate impervious surfaces to identify areas with both high temperatures and a high density of atrisk citizens for madison, wisconsin. Urban areas become significantly warmer than surrounding areas when there is less green cover and more hard surfaces which absorb, store and radiate heat. Monitoring and analysis of urban heat island using remote. A linear statistical model relating the nocturnal urban heat island uhi intensity of hamburg with meteorological conditions is constructed from observations taken by the german meteorological service dwd.
Jonathan winfrey, chris castro and zach bamman bsc 4932l. Evaluating the impact of the urban heat island on public health. To find the appropriate predictors the relationship between different meteorological variables and the uhi of hamburg is analyzed. Apr 23, 2020 an urban heat island occurs when a city experiences much warmer temperatures than nearby rural areas. Urban heat island assessment using the landsat 8 data. Planning urban heat island mitigation in boston executive summary erin coutts, kate ito, cecilia nardi, trang vuong to advance important resilience objectives, in 2015 the trust for public land, the city of boston, and a variety of partners launched a twoyear pilot project to inform and catalyze green infrastructure work in the metropolitan boston. Transportation and industry, contribute to the development of urban heat island wang 2001. This natural vegetation counteracts the urban heat island. Urban heat island mitigation programs that address economic disparities and incorporate local knowledge on neighborhood characteristics may be the most effective in reducing the health impacts of climate extremes and variability. View urban heat island research papers on academia. Mar 31, 2010 the effects of vegetative cooling and the urban heat island effect research by. The global urban heat island uhi data set, 20, estimates the land surface temperature within urban areas in degrees celsius average summer daytime maximum and average summer nighttime minimum as well as the difference between those temperatures and the temperatures in surrounding rural areas, defined as a 10km buffer around the urban extent. The concrete used for building traps heat causing urban heat islands uhi. The most striking characteristic of an urban microclimate is the urban heat island uhi effect.
Urban heat island city size and the urban heat island research on urban heat island effect. No, this is a separate phenomenon where cities are 68f warmer than surrounding rural areas. Urban heat island pictures download free images on unsplash. The phenomenon of an urban heat island was investigated by the use of landsatthematic mapper data sets collected over the metropolitan area of washington, dc. By combining the derived spectral albedos and temperatures, surface energy composites of. Many urban and suburban areas experience elevated temperatures compared to their outlying rural surroundings. They are formed because of the extra heat released from all the vehicles, machineries and industries located in big metropolitan cities.
The uniformity of this island shaped pattern generally indicates a few depressions due to the presence of particularly hot points i. Most building materials have higher heat capacities than rural materials effect on surface energy balance more effective at storing heat within their infrastructure release of heat overnight mitigation. Urban heat island is a concept where the urban area experiences warmer conditions than its surrounding regions. Abstract the urban heat island uhi has been known to have been around from as long as people have been urbanizing. The effects of vegetative cooling and the urban heat island effect research by.
The resulting epw file captures urban heat island effect. The output is a morphed weather file epw that captures urban heat island effect and is compatible with many building performance simulation programs. This thermal difference in conjunction with waste heat released from urban houses. Urban heat island effect 1 urban heat island effect 2 new york city 3 effects. Other authors also assume that the rural, or reference, point must possess less than 10% of constructed surface. Extreme heat events are on the rise, leading to urban centers becoming significantly hotter than surrounding rural areas. A statistical model for the urban heat island and its. This is due to anthropogenic heat release in the urban area from car exhaust, building cooling systems, and even metabolic heat. Its common in cities across the nation but its advancing in louisville at one of the fastest rates in the country. Londons urban heat island average summer pdf 30 november 2018 not available. Urban heat islands in china enhanced by haze pollution. Compendium of strategies describes the causes and impacts of summertime urban heat islands and promotes strategies for lowering temperatures in u. It defines and examines the characteristics of the urban heat island and, for the first time, creates an urban heat island index to quantify the extent and severity of urban heat islands for individual cities.
Higher temperatures attributed to the urban heat island effect increase the likelihood of nox and vocs forming smog, which has serious health consequences. Urban areas have higher temperatures during summer compared with adjacent rural communities, a phenomenon known as the urban heat island. The suns heat and light reach the city and the country in the same way. It defines and examines the characteristics of the urban heat island, and scientifically assigns a score based on atmospheric modeling for each census tract in and around most urban areas throughout the state. This tool is called this tool for heat island simulation. Here we can see no distinct heat island or cool island. Environmental protection agencys ofice of atmospheric programs. Jun 10, 2015 urban heat island uhi is one major anthropogenic modification to the earth system that transcends its physical boundary.
In 2015, calepa released a study entitled, creating and mapping an urban heat island index for california 5 mb, pdf. Strong winds reduce the temperature contrast by mixing together the city and rural air. The urban heat island uhi effect in metropolitan sydney, summer 201516. The urban heat island effect is present in virtually every major city in the world, and the workflow you developed in these lessons can be used to analyze other cities and other dates. The temperature difference between the city and surrounding areas is also a function of winds.
Urbanization has increased concerns about the uhi, particularly in terms of human health and a healthy environment. A gis extension model to calculate urban heat island. This fact is known as the urban heat island effect. Cities can mitigate urban heat island effects by using more pervious surfaces, vegetated and reflective roofs and planting. The footprint of urban heat island effect in china. Ppt urban heat island effect powerpoint presentation free. The urban heat island uhi is a well established phenomenon and it has been attributed to the reduced heating loads and increased cooling loads, impacting the total energy consumption of affected buildings in all climatic regions. The california environmental protection agency released a study that identifies areas across california experiencing hotter summer temperatures as a byproduct of urban development. The growth and conglomeration of cities in the past century has caused an increase in the intensity and impact of urban heat island, causing significant changes to the microclimate and causing imbalances in the temperature patterns of cities. The urban heat island may also increase cloudiness and precipitation in the city.
The uhi is considered to be the difference of air temperature values in the urban environment in relation to data recorded outside the city. A specific measure of this effect is the intensity of the difference between the maximum urban temperature and the minimum rural temperatureiii. Ozone can inflame the respiratory tract and increase the lungs susceptibility to infections, allergens, and other air pollutants. High temperature in the city centers than its surroundings known as the urban heat island uhi. Whether your biggest concern is likely to be rising seas, drought, or more intense storms depends on the region you live in, the urban heat island effect will soon be a worldwide phenomenon however, one thing not as many people. Causes of urban heat island formation urban heat island impacts on energy consumption, environmental quality, and human health resources for further information. Evaluating the impact of the urban heat island on public.
Widespread surface changes can reduce the urban heat island effect, helping residents adapt to urban heat. In australian cities, infill development and urban sprawl are leading to the loss of vegetation and the. The urban heat island uhi effect is a phenomenon that the land surface temperature in urban. An urban heat island, or uhi, is a metropolitan area thats a lot warmer than the rural areas surrounding it. Frontiers on the definition of urban heat island intensity. Downloads global urban heat island uhi data set, v1. The increased use of manmade materials and increased anthropogenic heat. It will show the population by census tract, the heat island effect calculated in degree hours per day celsius, and the average daily temperature increases fahrenheit. Analysis of the impact of urban heat island on energy. Nighttime urban heat island this conceptual map with overlaid isotherms lines of equal air temperature exhibits a fully developed nighttime atmospheric urban heat island.
The main cause of the urban heat island effect is from the. Technical information and interpretation download datafile technical information and interpretation, format. May 18, 2016 urban heat islands uhis, usually defined as temperature differences between urban areas and their surrounding rural areas, are one of the most significant anthropogenic modifications to the earths climate. The urban heat island effect, its causes, and mitigation, with reference to the thermal properties of asphalt concrete. The dotted red line indicates a traverse along which measurements are taken. A free powerpoint ppt presentation displayed as a flash slide show on id. Urban heat island map download kmz 15 mb once the map is open, click on urban areas to view the urban heat island effect by census tract. Think about the relief provided by sidewalk trees or the vegetation of a playground. The temperature difference is usually larger at night than during the day, and is most apparent when winds are weak. This compendium was developed by the climate protection partnership division in the u.
The urban heat island effect, its causes, and mitigation. Urban heat island simple english wikipedia, the free. A map of summertime temperature differences between urban and rural areas shows a striking similarity to the lights at night map. Spatial and social determinants of heat related mortality in new york city rosenthal, joyce klein increased rates of mortality and morbidity due to summertime heat are a significant problem in new york city nyc and for many cities around the world, and are expected to increase. The urban heat island uhi is a phenomenon that affects many millions of people worldwide. Urban heat islands uhi occur on the surface and in the atmosphere.
In 2015, calepa released a study entitled creating and mapping an urban heat island index for california pdf. Heat is created by energy from all the people, cars, buses, and trains in big cities like new york, paris, and london. An urban heat island, or uhi, is what happens when a city is warmer than the area around it. This study applies the extreme value theory to model and detect trends in extreme uhi events in hong kong, which have rarely been documented. The urban heat island uhi is the most studied of the climate effects of settlements. Urban heat islands are created in areas like these. The variation of urban geometry can influence the increase or decrease of this temperature difference, the wind speed and direction, the form of radiation re. The higher temperatures experienced in urban areas compared to the surrounding countryside has enormous consequences for the health and wellbeing of people living in cities.
Elevated global temperatures may thus be compounded by the additional stress resulting from the urban heat island. A case study in shenzhen and hong kong jinyeu tsou 1. Urban heat island intensity uh ii which is measured by the difference between the highest sustained ur ban air tem perature and the background rural tem perature 32. Urban heat islands ucar center for science education. Where urbanization is high urban heat island generate, in urban areas heat energy coming directly from sun trapped in the urban areas did not reflect back trapped in urban canyon at night this heat released by urban areas increased the atmospheric temperature of area oke et al. The temperature of urban areas can be significantly higher than that of the surrounding rural areas. This phenomenon is known as urban heat islands uhi allen et al. The urban canopy layer heat island iauc teaching resources. Can raise temperatures over cities 1 to more than 10 degrees f over that of surrounding areas. Basic characteristics of surface and atmospheric urban heat islands uhis4 how weather influences urban heat islands summertime urban heat islands are most intense when the sky is clear and winds are calm. The urban heat island effects can also be reduced by weather phenomona.
Even the case of tampa is not entirely incompatible with that view because there in winter are 12 percent more sunshine hours than in summer. Understanding and mitigating heat in urban areas pdf, epub, docx and torrent then this site is not for you. And we know the effect climate change has on peoples lives varies based on where you live. Urban heat island article about urban heat island by the. In fact after this bulletin, i will show you slides of the urban heat island in new york city.
As warming associated with urban development and climate. The highest values of the urban heat island intensity, in the region of 38 c, are often reached between about 11 oclock at night and 3 oclock in the morning figure 2. It happens because things in cities like concrete take longer to give off heat than things like trees, which are common outside of cities. An urban heat island uhi is a metropolitan area which is significantly warmer than its surroundings. Ppt urban heat island effect powerpoint presentation. Instructions obtain a weather file in energyplus epw format for a nearby site. The urban heat island effect is stronger at night and when there is not much wind. Global urban heat island uhi data set, v1 20 global 3year running mean groundlevel no2 grids from gome, sciamachy and gome2, v1 1996 2012 global annual pm2. Local governments face challenges in adapting to urban heat, however, including the complexity of the choices available, limited resources and authority. An urban heat island is a city or metropolitan area thats significantly warmer than its surrounding rural areas, due to human activities. Urban heat island outreach materials lists brochures, fact sheets, and other outreach materials on urban heat island formation, planning for excessive heat events, smart growth, and more reducing urban heat islands. Systems sustaina slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. The urban heat island represents the higher temperatures associated with urban spaces as compared with rural areas.
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